if __name__ == '__main__':
    num_1 = int(input("请输入第一个数字:"))
    operation = input("选择运算符 + - * /:  ")
    num_2 = int(input("请输入第二个数字:"))

    num_3 = 0
    if operation == '+':
        num_3 = num_1 + num_2
    elif operation == '-':
        num_3 = num_1 - num_2
    elif operation == '*':
        num_3 = num_1 * num_2
    elif operation == '/':
        num_3 = num_1 / num_2

    print("结果: %d" % num_3)
